As external conditions change, it becomes tougher to meet the three conditions that sociologists since the 1950s have considered crucial to making close friends: proximity; repeated, unplanned interactions; and a setting that encourages people to let their guard down and confide in each other. This is why so many people meet their lifelong friends in college.
Definitely is true for me so far. It's harder to make friends with the people I see at church only once a week or with people at work where politics or competition may come into play, and many of my friends from college are still some of the strongest relationships I have.